Abstract

Herring schools were surveyed hydroacoustically in
San Francisco Bay from early November 1989 through
mid March 1990. Seven large schools (>1000 tons) and
two smaller ones were detected. The total acoustic
biomass estimate based on visual integration was
58,100 tons. Merging with the independent spawn
escapement estimate yielded a "best" estimate of
64,500 tons.
Sixty-three samples, containing 10,239 herring, were
collected. Patterns evident in prior seasons
continue. Larger, older fish continue to dominate
early season schools. Males continue to be
numerically superior during the first half of the
season. Mean size and weight at age suggest
conditions following the 1988-89 season were not
favorable for growth.
Contrary to forecasts, the 1988 year class
recruitment strength was high; second only to the
1982 year class. Although still being validated,
forecasts suggest the 1989 year class will be strong
and the 1990 year class will be extremely weak. (64pp.)

Item Type:

Monograph or Serial Issue

Title:

Pacific herring, Clupea harengus pallasi, studies in San Francisco and Tomales Bays, April 1989 to March 1990